This research is broadly concerned with the potential role of the parabrachial nucleus (PBN) as a substrate for the observed links between affect and balance. Two major areas of investigation are identified: physiological and anatomical. Vestibulorecipient cells have been found in the portion of PBN reciprocally connected with the central nucleus of the amygdala (CeA). Neurons in this region express a variety of unique responses, including static position sensitivity, and bias and modulation responses to off-vertical-axis rotations. The present research is concerned with dynamic, otolith-derived responses of PBN units during OVAR. We will test the general hypothesis that static position sensitivity and responses to periodic rotational stimuli predict dynamic otolith responses during OVAR. Additionally, the vestibular nuclei-PBN-CeA network is not well characterized anatomically. We propose to study the efferent organization of the PBN with respect to the vestibular nuclei and CeA, to determine whether there exist collateralized projections from PBN to both areas, and the relationships between cell bodies projecting to each area. We will also test the hypothesis that vestibulorecipient PBN neurons project to the CeA through both tract tracing and antidromic activation of PBN efferents to CeA. [unreadable] [unreadable]